Follow these instructions to make sure that your letters and parcels are delivered safely:
Large letters and parcels
A large letter can be up to 360mm x 260mm in size, 20mm thick and weigh up to 500 grams. Anything larger than this is a parcel. Parcels need to be packed carefully so that their contents arrive safely. Post offices sell enough special packaging materials to wrap almost anything you can imagine!
Your local post office will calculate the postage cost, or you can use the postage calculator on the Australia Post website.
Why the postcode is important
Postcode numbers on envelopes are essential to ensure your letter arrives as quickly as possible. Every town and suburb has a postcode and each state / territory has its own distinctive numbers.
Printed or typed addresses do not need to use the postcode squares on the envelope, but the postcode should be on the last line, after the suburb and state / territory.
Postcodes can be found on the Australia Post website.
What about the postage?
Make sure you have put the correct amount of postage on your mail. Your letter's length, width, thickness and weight will determine how much postage you pay. A small letter must be no larger than 240mm long and no thicker than 5mm. It must also weigh less than 250grams. Take your letter or parcel to a post office, or use the postage calculator on the Australia Post website to find out how much postage you will have to pay.
When you receive a Reply Paid envelope with a letter, it means that the business that sent it to you has been issued with a special number and will pay for the postage when they receive your reply in the envelope provided. (Sorry, you can't use a Reply Paid envelope to send a letter to anyone else!)